الفهرس 
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Abstract
Marigold flowers have a great importance in horticultural sector as an ornamental plant which is not only used in flavoring of foods but also important in pharmaceutical and medicinal industries. The current study was carried out in pots under greenhouse conditions to evaluate the response of marigold seedlings to foliar application of salicylic acid (SA) and potassium humate (KH) in two media (M1: coco peat+ sand and M2: coco peat + vermiculite). Physiological and biochemical parameters were evaluated along with the content of volatile oil and beta-carotene of marigold plants. Different levels of salicylic acid (50, 100, 150 and 200 mg/L.) and potassium humate (500, 1000, 1500 and 2000 mg/L.) under two growing media were foliar applied in the current study. The foliar application of SA and KH on marigold seedlings significantly increased all studied vegetative growth parameters except plant height, which remained non-significant. The enzymatic antioxidant activities also were enhanced by foliar application of SA and KH. These activities were increased in case of KH up to 1500 mg/L., whereas up to 200 mg/L. in case of SA except for catalase (CAT). Photosynthetic parameters and chlorophyll fluorescence were decreased with increasing levels of SA up to 200 mg/L. but this trend was typically the opposite for KH under both growing media. Concerning, volatile oil content of marigold flowers increased by foliar application of SA at 100 mg/L. The highest oil yield was obtained after foliar applied 1000 mg/L. of KH. Thus, the production of marigold flowers could be achieved using poor growing medium like sand. Therefore, studies concerning different alternatives growing media are needed particularly the eco-friendly and cheap materials.